Chemically stabilized film
AssigneeW. R. Grace & Co., Cryovac Div.
InventorsWalter B. Mueller, Henry G. Schirmer
Life of this patent
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Abstract
In a multilayer flexible film suitable for medical solution packaging, film-derived extractables are controlled by the use of a small amount of a high molecular weight stabilizer in the outer layer of the film. Solution pH can be controlled by the addition of a carbonate of an alkali metal to at least one intermediate adhesive layer and/or the core layer of the film.
Claims4
In a multilayer flexible film comprising a sealant layer, a core layer comprising very low density polyethylene, an outer layer of a flexible polyester or copolyester, a first adhesive layer bonding the core layer to the sealant layer, and a second adhesive layer bonding the core layer to the outer layer, the improvement comprising the inclusion in the outer layer of between about 0.3% and 1% by weight of the outer layer of a high molecular weight stabilizer.
A method of producing a multilayer film comprising:
- (a) blending a flexible polyester or copolyester with between about 0.3% and 1%, by weight of the polyester or copolyester, of a high molecular weight stabilizer;
- and
- (b) coextruding a multilayer film comprising a sealant layer, a core layer comprising very low density polyethylene, an outer layer containing the blend of (a), a first adhesive layer bonding the core layer to the sealant layer, and a second adhesive layer bonding the core layer to the outer layer.
Dependencies are inferred from the claim text.